1. Field of the Invention
The present invention relates to a hypocycloid drive device, and more particularly to a hypocycloid drive device powered by pulling a tilt cord to adjust slat angles for a venetian blind.
2. Description of Related Art
Venetian blinds are made of slats suspended between parallel ribbons and are hung over windows. A user can adjust the slat angle to regulate the light transmitted into a room. A conventional drive device for adjusting the slat angle comprises a worm gear, a worm and a tilt cord. The worm is adapted to couple to an end of a tilt rod that will change the slat angle. The worm gear is meshed with the worm and is operated by the tilt cord. When a user pulls the tilt cord, the tilt cord rotates the worm gear, and the worm gear rotates the worm. A tilt rod rotates with the worm to change the slat angle of a venetian blind.
The elements of the conventional drive device are arranged and assembled in at least two axial directions. Specifically, the worm and the worm gear are not arranged co-axially. Such a structure of the drive device occupies a large volume.
The drive device and the tilt rod are installed in a head rail of the venetian blind. Therefore, the head rail of the venetian blind also must be large enough to hold the conventional drive device. The enlarged head rail of the venetian blind will be inconvenient to mount or decorate.
To overcome the shortcomings, the present invention provides a hypocycloid drive device for adjusting the slat angle in a venetian blind to mitigate or obviate the aforementioned problems.
The main objective of the invention is to reduce the size of the drive device for adjusting slat angles in a venetian blind.
Another objective of the invention is to reduce the size of a venetian blind head rail.
The foregoing objectives are achieved by using a hypocycloid drive device to adjust the slat angle of the venetian blind.